A voltage regulator (VR) circuit generates a voltage rail at a rated voltage and current. It consists of several voltage regulator cells that function in parallel. Each of these cells further comprises several interleaved phases of DC-DC converters. There is a feedback control topology associated with each of these cells.
Such a common VR topology senses the load current and sets identical current references for all the phases within the cell. It also generates the delayed duty cycles for each of these phases required for interleaved operation. Conventionally, each of these cells in a circuit is implemented to share the load current equally. This results in a power efficiency that is a strong function of the load, resulting in low efficiency under low load conditions. Maximum efficiency is achieved at a certain load condition and any other load condition results in low power efficiency.
Attempts to improve efficiency in isolated power supply modules over a broader range of load conditions, such as by switching cells on and off, has proven to be of limited benefit. Such power supply modules (cells) must be discretely implemented and are limited to a few in number. Control requires the use of fast analog ICs since the number of power supply units operated in parallel is less. In integrated implementation, several tens of VR cells may need to operate in parallel. Extending such an implementation to an IVR application is not practical Lacking in the prior art is a simple power circuit with a hierarchical control for improving efficiency and optimizing performance under all load conditions in an integrated VR of many cells.
Although the drawings and following description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly.